M.,
Our daughter, Meg, was born with one of these 'strawberries' on her forearm and it is about an inch in diameter. In the begining months it did seem to grow upward and get more red, but didn't really change in diameter. We took her to a skin doctor to see what we could do to remove it, and she assured me that it would just go down over time, become less red and full of blood, and eventually just disappear. She said that it was just an abnormal collection of blood vessels and that if she tried to do surgery at 6 months or so it would just be a bloody mess with a scar for life. She suggested that if I really wanted to do something about it, we could wrap the arm in an ace bandage to see if it would cause it to go down. Well, we tried that for like 2 weeks, but the area just got irritated and formed a scab. Then one day the scab got scraped and it started shooting out blood (after all this is a collection of blood vessels, right!) THAT was scary, but with pressure, the bleeding stopped. After that we just have left the dang thing alone. Now our Meg has just turned 4 and her hemangioma is only slightly a bump on her arm and it is almost the same skin color as the rest of her, just a little more pink.
So, I guess my advice is this - get a second opinion if it will ease your mind. I think the dermatologist was a good choice to visit (instead of a like another pediatrician) since this is their specialty. My other advice is that over time, you won't even notice that she's got a strawberry - my daughter is now used to telling other curios kids that she has a birthmark, but it will be gone in a few years.
Please feel free to contact me if you want the dermatologists contact information or have any questions. Good luck!! ~ K.